Upsetting of metal tubes, rods, or the like



March 14, 1944.

W. J. CORMODE UPSETTING OF METAL TUBES, RODS, OR THE LIKE Filed April6,. 1943 Fig.1

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.IZLUGRIZOI kl, J. Cormade Patented Mar. 14, 1944 UPSETTING OF DIETALTUBES, RODS, OR

THE LIKE William John Cormode, Erdington, Birmingham, Y England,assignor to T. I. (Group Services) Limited, Birmingham, EnglandApplication April 6, 1943, Serial No. 482,061 In Great Britain June, 23,1942 (or. res- 3) 1 Claim.

This invention relates to the upsetting of metal. tubes, rods, bars,extruded sections or the like. To elucidate the problem with which theinvention is concerned, the simple instance of forming an externalcollar or flange on one end of a tube will be described. One mode ofprocedure in this instance is to place the end of the tube in a die andapply endwise pressure to the tube. Prior to or during the operation thetube end is suitably heated, and the interior of the tube is supportedby a plug or mandrel. The die consists of a block of metal in which isformed a cylindrical cavity of the same diameter as the required flange,and of at least the same depth as the thickness of the flange. If theaxial thickness of the flange to be produced is substantially greaterthan the wall thickness of the tube, and at the same time, the diameterof the flange to be produced exceeds the outside diameter of theoriginal tube by an amount substantially more than 50% of the thicknessof the tube, the flange will result mainly from buckling of the metaland will consist of a series of folds. For many purposes, however, andespecially when machining operations have subsequently to be performedon the flange this mode of formation is unsatisfactory. What is requiredis that the metal displaced from the main portion of the tube by endwisepressure shall flow along regular lines without the formation of foldsor wrinkles. So far as I am aware, this requirement has not hithertobeen satisfactorily met, especially in the working of metal tubes, barsor the like made from aluminium or aluminium alloys or magnesium alloyswhich are capable of being worked at moderate temperature obtained fromheat imparted through the die.

The object of my present invention is to enable a satisfactory flowcondition to be obtained in the metal (and particularly such metals asthose above-mentioned) in a simple and convenient manner.

The invention comprises an upsetting means comprising the combination ofa die, and a work support which is slidable relatively to the workpieceeither freely under pressure exerted by the growing upset portion of thework-piece or at a controlled rate by mechanical means.

In the accompanying sheet of explanatory drawings:

Figures 1 and 2 are diagrammatic sectional side views illustrating indifierent stages one mode of carrying the invention into efiect.

Figures 3 and 4 are respectively similar views tol 'iguresland'Zillustrating another mode of carryingout the invention. v

The essential feature of myinvention will readily be understood fromconsideration of the example shown in Figures 1 and 2.- Let it besupposed that itis required to form on one end of a metal tube a madefrom an aluminium, magnesium, or other like alloy, a flange whose axialthickness is several times greater than the wall thickness of the tube,and whose diameter exceeds the outside diameter of the metal tube by anamount substantially more than 50% of the thickness of the tube.

In carrying the invention into effect as shown in Figures 1 and 2, Iemploy a die b having a cylindrical cavity 0 adapted to accommodate theend portion of the tube a on which the flange is required, the cavitybeing of any convenient depth and having a diameter equal to that of theflange to be produced. The die b is heated to an appropriate temperatureby electrical or other means (not shown). Extending coaxially throughthe die cavity 0 is a plug or mandrel d adapted to fit and support theinterior of the tube a. If desired the plug or mandrel d may be securedto the base of the die b, but preferably it is free to move axiallyduring the formation of the required flange on the tube a. The inner endof the die cavity around the plug or mandrel d is closed by a shoulder ein the die b. Into the annular space between the exterior surface of thetube a and the peripheral wall of the die cavity 0 is inserted atube-supporting sleeve This sleeve fits the tube a. closely (though itis free to slide along the tube) but it may fit the die b loosely. Tobegin with the inner end of sleeve f is arranged to occupy a position sothat its distance from the closed inner end of the die cavity 0 ispreferably about equal to the wall thickness of the tube a. The sleeve 1is preferably provided with a flange as g or other stop at its outer endto prevent it moving further into the die cavity 0. Pressure is thenapplied to the outer end of the tube a. The first effect of thispressure is to cause the inner end of the tube a to spread laterallyinto the space bounded by the die b and the inner end of the sleeve ,f.and to fill this space. So long as the depth of this space is notsubstantially greater than the tube-Wall thickness, the metal will flowinto it without buckling or folding. Thereafter under the endwisepressure on the tube a the metal continues to spread laterally and tocause the sleeve to recede by pressure on the inner end of the sleevewhile the flange it (Figure 2) formed by the spread metal is growing inaxial thickness. The operation is continued until the desired thicknessof the flange h is obtained. When a section is made of a flange thusformed the metal is found to be free from buckling or folding, and theflow-lines of the metal are in the main substantially parallel with thetube It will be apparent that the invention is capable of producingupsets such as flanges or collars on a tube, rod, extruded section, orother work-piece of long or short length and in a variety of positions.Thus such upsets may be formed at the ends or at one or more positionsalong the work-piece. In the latter case the die b is adapted to allowthe tube a or other work-piece to extend through it as shown in Figures3 and 4, the end of the work-piece, opposite to that to which thepressure is applied being supported by a fixed stop i, and the inner endof the cavity between the work-piece and the inner periphery of the diebeing closed by plates as 7'. Also internal flanges, collars or otherupsets may be formed at the ends or at positions along the length oftubes or other hollow workpieces by appropriate modification of the die.In this case the outer surface of the work-piece is supportedby-the die,and the inner surface (adjacent to the upset) by a slidable plug ormandrel. Moreover, whilst it is satisfactory to employ a freely slidablesupport whose movement is caused by the increasing upset, it may in somecases be desirable to control the movement of the support in which caseit may be actuated at an appropriate rate by any convenient mechanicalmeans.

c Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

Means for upsetting a metal tube, rod, bar, Y

the surface of the work-piece adjacent to the upset is continuouslysupported during an endwise pressing operation on'the work-piece, andwhich is slidable relatively to the work-piece while the upset is beingformed.

WILLIAM JOHN CQRMODE.

